1996 GMC Safari Owner's Manual - Page 257

NOTICE: If you use an improper coolant mix, your engine could overheat and be badly damaged. The repair cost wouldn't be covered by your warranty. Too much water in the mix can freeze and crack the engine, radiator, heater core and other parts. Checking Coolant If you have to add coolant more than four times a year, have your dealer check your cooling system. I NOTICE: If you use the proper coolant,you don't have to add extra inhibitorsor additives which claim to be improve the system. These can harmful. When your engine is cold, the coolant level should be at ADD, or a little higher. When your engine is warm, the level should be up to FULL HOT, or a little higher.